Dioptase

General Information: Chemical Formula:CuSiO2(OH)2 Composition:(Molecular Weight = 157.64 gm)Silicon 17.82 % SiCopper 40.31 % CuHydrogen 1.28 % H Oxygen 40.60 % O  Empirical Formula: CuSiO2(OH)2 Environment:Secondary mineral in oxidized zones of copper deposits. Locality:Tsumeb and Cochab, Namibia. Altyn Tube, Russia. Name Origin:From the Greek, dia - "through" and optomai - "vision."Physical Properties: Cleavage:[1011] Good Color:dark blue green, emerald green, or turquoise. Density:3.28 - 3.35, Average = 3.31 Diaphaniety:Transparent to translucent Habits:Massive - Uniformly indistinguishable crystals forming large masses., Cryptocrystalline - Occurs as crystals too small to distinguish with the naked eye., Crystalline - Coarse - Occur s as well-formed coarse sized crystals. Hardness:5 - Apatite Luminescence:None. Luster:Vitreous (Glassy) Streak:greenMore details...

C SiO2(OH)2